From 4fb0d7abfc0fd12c45621fe5774d400a053d7ba9 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sun, 23 Feb 2020 17:50:57 -0500
Subject: [PATCH] deconflict `value` parameter in contextual bindings (#4452)

---
 CHANGELOG.md                                        |  1 +
 .../render_dom/wrappers/InlineComponent/index.ts    | 13 ++++++-------
 .../deconflict-contextual-bind/Widget.svelte        |  3 +++
 .../samples/deconflict-contextual-bind/_config.js   |  3 +++
 .../samples/deconflict-contextual-bind/main.svelte  |  8 ++++++++
 5 files changed, 21 insertions(+), 7 deletions(-)
 create mode 100644 test/runtime/samples/deconflict-contextual-bind/Widget.svelte
 create mode 100644 test/runtime/samples/deconflict-contextual-bind/_config.js
 create mode 100644 test/runtime/samples/deconflict-contextual-bind/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3f4460cde48e..2166ca4c9c96 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+* Deconflict `value` parameter name used in contextual bindings ([#4445](https://github.com/sveltejs/svelte/issues/4445))
 * Fix dev mode validation of `{#each}` blocks using strings ([#4450](https://github.com/sveltejs/svelte/issues/4450))
 
 ## 3.19.0
diff --git a/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts b/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts
index f1c57ed09415..28b3c938f9d3 100644
--- a/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts
+++ b/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts
@@ -332,8 +332,7 @@ export default class InlineComponentWrapper extends Wrapper {
 				contextual_dependencies.push(object.name, property.name);
 			}
 
-			const value = block.get_unique_name('value');
-			const params: any[] = [value];
+			const params = [x`#value`];
 			if (contextual_dependencies.length > 0) {
 				const args = [];
 
@@ -349,23 +348,23 @@ export default class InlineComponentWrapper extends Wrapper {
 
 
 				block.chunks.init.push(b`
-					function ${id}(${value}) {
-						${callee}.call(null, ${value}, ${args});
+					function ${id}(#value) {
+						${callee}.call(null, #value, ${args});
 					}
 				`);
 
 				block.maintain_context = true; // TODO put this somewhere more logical
 			} else {
 				block.chunks.init.push(b`
-					function ${id}(${value}) {
-						${callee}.call(null, ${value});
+					function ${id}(#value) {
+						${callee}.call(null, #value);
 					}
 				`);
 			}
 
 			const body = b`
 				function ${id}(${params}) {
-					${lhs} = ${value};
+					${lhs} = #value;
 					${renderer.invalidate(dependencies[0])};
 				}
 			`;
diff --git a/test/runtime/samples/deconflict-contextual-bind/Widget.svelte b/test/runtime/samples/deconflict-contextual-bind/Widget.svelte
new file mode 100644
index 000000000000..3aaa59b74757
--- /dev/null
+++ b/test/runtime/samples/deconflict-contextual-bind/Widget.svelte
@@ -0,0 +1,3 @@
+<script>
+	export let prop;
+</script>
diff --git a/test/runtime/samples/deconflict-contextual-bind/_config.js b/test/runtime/samples/deconflict-contextual-bind/_config.js
new file mode 100644
index 000000000000..7602cde02323
--- /dev/null
+++ b/test/runtime/samples/deconflict-contextual-bind/_config.js
@@ -0,0 +1,3 @@
+export default {
+	preserveIdentifiers: true
+};
diff --git a/test/runtime/samples/deconflict-contextual-bind/main.svelte b/test/runtime/samples/deconflict-contextual-bind/main.svelte
new file mode 100644
index 000000000000..fe91deca17f1
--- /dev/null
+++ b/test/runtime/samples/deconflict-contextual-bind/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	import Widget from './Widget.svelte';
+	const values = ['foo', 'bar'];
+</script>
+
+{#each values as value}
+	<Widget bind:value/>
+{/each}